Pneumatic suspension system



`D`e`c. 29, i953 J. A. McNALLY 2,664,257

PNEUMATIC SUSPENSION SYSTEM Original Filed April 29, 1949 3 Sheets-Sheetl JAMES A. MC NALLY WMM , Dec. 29, 1953 J, A, MCNALLY 2,664,257

PNEUMATIC SUSPENSION SYSTEM Original Filed ApIIil 29, 1949 5Sheets-Sheet 2 INVENTOR. JAMES A. Mc NALLY ATTORNEYS J. A. MCNALLYPNEUMATIC SUSPENSION SYSTEM 5 Sheets-Sheet I5 A v INVENTOR. JAMES A. MCNALLY x. 2M; 2f ATTORNEYS Dec. 29, 1953 Original Filed April 29, 1949Patented Dec. 29, A1953 PNEUMATIC SUSPENSION SYSTEM James A. McNally,United States Navy Arlington, Va.

Original application April 29, 1949, Serial No. 90,522. Divided and thisapplication June 20, 1952, Serial No. 295,380

(Granted under Title 35, U. S. Code (1952),

sec. 266) 3 Claims.

This application is a division of applicationv Serial No. 90,522y ledApril 29, 1949, for Pneumatic Suspension Systems.

The present invention relates to machine mounting systems and moreparticularly to pneumatic mounting systems which are sub jected tosevere shock loading.

Presently available machine mounting systems usually employ rubber orspring steel members to carry the weight of the machine and to isolatethe machine from the supporting structure. However, such structures arein no Way adjustable to adapt the mounting for changing conditions.

Mountings for mobile engines and especially those employed in combatvehicles .are suojected to severe shocks which produce high inertiaforces Which must be transmitted to the supporting structure, and forthe purposes of shock transmission the mounting must be extremely stiff.However, where it is desired to prevent the transmission of vibrationthrough the mounting, the mounting must possess a lower naturalvibration frequency than the vibration produced by the machine, whichcondition is produced by a very resilient mounting. Furthermore, machinemountings in cramped conditions are difficult to align so as to producethe desired leveling of the machine because the machine must often beeccentrically positioned on its base.

rIhe mounting of the present invention pro vides a soft mounting forisolating normal vibration of the engine by a plurality ofindividualized resilient bladders which are adapted to be inflated witha gas. The bladders are enclosed in separable metallic receptacle whichlimit the unrestrained movement of the bladder and transmit any shockloading through the metal receptacle. Since the individual light andresilience of the units may be changed by changing the pressure of thegas within the unit, mounting difculties caused by an irregularfoundation or unsymmetrical distribution of weight may be easilycompensated for and corrected.

It is an object of the present invention to provide a machine mountingsystem in which the machine is pneumatically supported by a plurality ofindividualized inflatable elements.

lt is a further object of the present invention to provide a resilientmachine mounting system in which eccentric weight loading may be easilycompensated for.

It is a still further objectof the presentk nvention to provide aresilent machine mounting which normal vibration of the machine iseffectively isolated from the supporting structure and which alsotransmits shock forces satisfactorily.

Other objects and advantages of the present invention will be made moreapparent by refer ence to the following description and to the annexeddrawings in which:

Fig. l is a showing of a machine mounted in accordance with the presentinvention;

Fig. 2 shows a mounting element partly in section suitable for use inthe present mounting system;

Fig. 3 is a side view, partly in section, of the mounting element shownin'Fig. l;

Fig. 4 is a showing of a hanger mounting ein ploying the presentinvention;

Fig. 5 is a sectional view taken on line 5-5 of Fig. 4;

Fig. 6 is a mounting element similar to that shown in Fig. 4 exceptarranged for base mounting;

Fig. 7 is a showing of a modified mounting element in accordance withthe present invention; and

Fig. 8 isa section `taken on line 8-3 of Fig. 7.

Referring now to Fig. 1 the machine 28 is provided v/ith a bed 26 and issupported on the foundation 21 by means of a plurality of individuallyinflatable elements Il which are attached to the foundation and themachine bed. The weight of the machine 28 is supported by a plurality ofresilient gas-filled bladders within the mounting elements Il, so thatthere is no metallic contact between the bed and the foundation undernormal operating conditions and the vibration of the machine iseiiectively isolated from the foundation. The machine 28 may be readilyadjusted to a .level position by regulating the pressure intheindividual elements ll so that inequalities in weight loading among theseveral elements regardless of the cause may be compensated withoutdismantling the machine or even affecting its operation if the machineis in operation when the adjustment is made. It will be appreciated thatthe mounting unit under the heavier loading is inflated to a higherpressure and therefore exerts a larger restraining force on the machine.Stresses caused by the application of unequal vibrational loading in thebase are substantiallyreduced because theweight distributionl and theresilience of the support system are proportioned so as to .cause/the.Aamplitude of lthe upturned sides and may be of any convenient at thejunction thereof.

dimensions and shape, such as rectangular,

cylindrical, or semi-ellipsoidal. The rectangular unit shown is intendedto be illustrative, and the invention is not considered limited thereto.The upturned sides are slotted to provide a serrated edge such as aplurality of teeth which are adapted to intermesh with similarprojections on a similar unit. The dimensions of the teeth and the slotsillustrated in Fig. l. are proportioned to provide substantialclearances between adjacent teeth to provide for lateral movementbetween two ceptacles. The teeth of each receptacle I2 are substantialduplicates and when such receptacles are mated with one another, theteeth intermesh thereby facilitating assembly and alignment of the unitsand erection of machines mounted thereon.

When two receptacles I2 are placed open side to open side, a cavity isformed between the two. A bladder 30 of resilient impervious materialsuch as natural or artificial rubber molded to snugly fit the cavitythus formed is equipped with an inating stem 33. The inating stern 33may be equipped with a check valve of the type usually employed inautomobile tubes or any other suitable form, and a fabric or wirereinforcing strip 32 is molded into` the bladder at the area of itssurface corresponding to the area of the serrated edges on the cavity.The bladder 30 is inserted within the cavity and thestem 33 extendsthrough the opening I4 in one of the receptacles I2. The opening Ill inthe other receptacle I2 is not used, andthe bladder3 is reinforced atthe point corresponding -tothe opening.

The receptacle I2 is provided with a base plate I6 containing aplurality of mounting holes Il which is used to attach the mountingelement II to the bed of the machine and to the foundation by means ofbolts or screws. The attachment of the receptacles I2 should beseparable from the foundation and the bed of the machine to facilitateinspection and repair of the unit, although welding or other permanentsecuring'means may be employed for the purpose if desired.

The receptacles I2 are also equipped with longitudinal anges I3projecting from opposite outside surfaces, which flanges are engaged bythe retaining plates 20 which serve to limit the separation of thereceptacles to a safe value. The plates 26 which are attached to themounting element II by means of bolts 23 and nuts 2G are provided with alongitudinal groove 2l which is adapted to receive the flange I3 of onereceptacle and a projection 22 adapted to engage the flange I3 of theother receptacle at the limit of travel of one receptacle relative tothe other, but entirely out of contact with the flange at all othertimes. A clearance is provided in the plate 2E! to prevent mechanicalcontact between the plate 2i) connected with one receptacle i2 and theother receptacle I2 `except at the-limit. of travel, thereby preventingthe transmission of vibration therebetween. f-

Figs. 4 and 5 show a modification of themachine mounting element whichis arranged to suspend the machine from an overheadsupportjuxtapositioned reing structure. In this structure, thereceptacles 42 and i3 are identical semi-spherical shells each having aserrated edge consisting of a plurality of regular crenations on itsedge which when two such receptacles are placed together will form asphere having intermeshing projections The receptacle i3 is attached toa yoke i4 adapted to be bolted to the stationary fixture 45 by the bolts@5. The stationary fixture e5 is attached to the supporting structure bythe bolts l. The receptacle 42 is provided with a buttress 58. a surfacewhich is a portion of a sphere, which surface is normally held clear ofthe surface de of the stationary fixture except when the unit issubjected to shock loading. The yoke 52 is secured to the buttress 138and is provided with the threaded shoulder 33 adapted to receive the rodattached to the machine. A bladder 5S is provided which ts the cavitybetween the two receptacles 42 and d3, and has a stem 5? passing throughthe hole EB in the yoke 54. The function and construction of the bladder56 is similar to that previously discussed and the reinforcing strip 59is included in the bladder 56 adjacent the junction of the shells 42 and43.

The spherical element allows free movement in any direction within safelimits and in addition, allows a limited rotation of the rod about themounting element in any direction. The rotation of the element islimited by the vertical clearance between the serrated edges such as thecrenations in the receptacles, while lateral movement is limited by thelateral clearances of the convolutions and upward movement of the rod 54is limited by the clearance between the buttress i3 and the surface i3in the stationary xture 45.

Fig. 6 shows a spherical shock mounting similar to that shown in Figs. 4and 5 arranged to be located beneath the machine. The receptacles 60 and6I are similar to the receptacles 42 and d3 except that they areprovided with circular threaded flanges S4, 65 perpendicular to the axisof symmetry of the receptacle. The outer edge of the ange is threaded tooperatively engage the threaded collar 66 of the retaining cup 6T. Theretaining cup B'I is a metallic tube having a threaded collar B3 ofreduced diameter at one end of the tube and a shoulder 68 of an insidediameter substantially smaller than the diameter of the circular flangesso as to present substantial contact surface therebetween to preventexcessive separation of the receptacles. The mounting plates l0, Il areattached to the receptacles perpendicular to the axis thereof and plate'I0 is of such a diameter as to pass freely through the shoulder whenthe unit is assembled as described hereinafter.

The mounting plate may be secured to the machine bed or the foundationby any convenient means, such as bolting.

Each of the receptacles Se, 6i is provided with an opening 'I2 in thewall between the threaded flange and the attachment of the mountingplate suitable for the passage of the stem l of the bladder. The bladderis molded to fit snugly within the cavity formed by the two receptacleswhen assembled and is provided with a reinforcing strip molded thereinaround its horizontal diameter to prevent the bladder from being forcedinto the clearance spaces of the serrated edges between the receptacles,as in the modiyfications previously discussed.

The element 'I5 is assembled by screwing the retaining cup 61 over thethreaded flange 84 of the receptacle 69 so that the flange is within theretaining cup. When the bladder has been inserted and the machine placedon the mount, the retaining cup 6l is screwed onto the flange 65 of themating receptacle 6|.

Figs. 7 and 8 show a further modification of the present invention. Theupper support member 83 is provided with a mounting plate 88 adapted tobe attached to the bed of the machine and L a concave surface 89 havinga surface conformation which is a portion of the surface produced byrevealing an oblate ellipse about its minor axis. The base supportmember 84 is provided with a base 9D adapted to be attached to afoundation and contains a concave surface 9| which surface is similar tothe surface 89 in the upper support member 83.

The bladder 95 situated in the cavity between the surface 89 and thesurface 9| is molded in a spherical form and is provided with areinforcement 96 which prevents the expansion of the bladder but allowsfree flexing thereof. The bladder 95 is equipped with an inflating stem9i which passes through an opening in the bottom support member 84 andis provided with a fixture 98 for attachment of an inflating means.

The upper support member 83 is provided with a horizontal flange l|l|and the base support member 84 is provided with a matching flange |62 toprotect the bladder 95 and to transmit shock loading. The retaining ringIlla is attached to the flange |02 on the base support member 85 and isprovided with a shoulder |85 adapted to engage the upper surface of theflange ||l| so as to prevent excessive separation of the flanges lilland |02. If the upper support member 83 is laterally displaced from thebase support member 8d, the flange |0| strikes the inner surface of theretaining ring |03 and thus prevents excessive lateral displacement.

It will be apparent to those skilled in the art that many modificationsof the present invention are possible. For instance, the dimensions ofthe mounting units may be varied in proportion to the weight of themachine to be supported and that the unit may be readily modified tosuit a particular mounting position if it is desired to do so. Thebladder may be composed of either natural or synthetic rubber, and thereceptacles and mutual parts may be made from steel or brass asconditions warrant. The individual stems may be extended to terminate ata concenient location by means of tubing.

It will also be appreciated that in the event of the failure of a unit,the remaining units may be inflated sufficiently to allow continuedoperation if such operation is necessary. While the bladders areprotected from excessive pressures by the mating contact surfaces, themachine may be operated for short times even in the event of failure ofall the units because the units are self-centering when the flanges arein contact with each other.

The invention described herein may be manufactured and used by or forthe Government of the United States cf America for governmental purposeswithout the payment of any royalties thereon or therefor.

What is claimed is:

1. A resilient mounting comprising a rst hemispherical shell and asecond hemispherical shell having abutting mating edges formed in aplurality of crenations, said first and second shells being positionedin open ended vertical juxtaposition with said crenations intermeshed toform a substantially spherical cavity therebetween, said rst shell beingpositioned below said second shell, a spherical impervious bladderwithin said spherical cavity, the stationary fixture for attachment toan overhead supporting structure and having a concave limit stop portiontherein, said first shell having an integral supporting U-shaped memberattached to said stationary fixture, said second shell having anintegral buttress protruding therefrom and partially projecting into theconcave limit-stop portion of said stationary fixture, bladderreinforcing means adjacent the abutting edges of said rst and secondshells, and valve means to permit inflation of said bladder to separatesaid first and second shells, said intermeshed crenations and thecoaction of the buttress of said second shell with the concavelimit-stop portion of said stationary xture limiting the lateralmovement of said second shell relative to said first shell to apredetermined degree.

2. A resilient mounting as defined in claim 1 but further characterizedby said crenations being of equal depth and shape.

3. A resilient mounting as claimed in claim 1, but further characterizedby the buttress of said second shell having a machine supporting yokesecured thereto and extending downwardly around said rst shell and saidsupporting U- shaped member, a supporting rod secured to said machinesupporting yoke, whereby a machine may be resiliently mounted to saidoverhead supporting structure.

JAMES A. McNALLY.

No references cited.

